Wood-pulp grinder



W.-R. TlDlVlARSH- WOOD PULP GRINDER.

APPLICATION FILED AUG.3I, 1920.

Patented Nov. 29', 1921.

2 SHEETg-SHEET 1- fame whoa 35 M (M/tom pm] Patented Nov. 29, 1921.

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W. R. TIDMARSH WOOD PU-Ll GRINDER.

APPLICATION FILED Aue.31, 1920. 1,398,753.

UNITED ATE PATEN ww- WILLIAM RITCHIE TIDMARSH, or BANGOR, MAiNE, ssIGno'It or emanate TO r UNION IRON WQRKS, or BANGOR, IJI N Q CORPORATIONOF MAINE.

ToaZZwfiOmitW Lay concern: 7 Be it known that 1, WILLIAM' RrroHIn TIDMARSH, a citizen of the UnitedStates,

residing at Bangor, in the county of Penobsoot, State of Maine, have inventedcertain grinders used in r making the so-called mechanical pulp employed in the manufacture of newsprint and'other low grade papers, and particularly to that. type of grinder in which a series of wood receiving pockets are radially disposedabout a grindstone. More specifically it relates to means for automatically retracting the pressure foot and opening the door of a pocket as soonas the wood within that pocket has been groundfaway.

In the grinding of mechanical wood pulp,

the wood is forced against the peripheral face of a rapidly rotating grindstone, and the ground pulp carried a'wayto screens by a stream of water which plays upon the stone during the grinding. In one common type of grinder, a series offrom'two to four pockets is radially, disposed aboutthe up-.

per half of the grindstone casing Into i' these pockets is placed'the wood to be ground, the doors of the pockets closed, and;

a plunger or pressure foot within the pocket brought to bear against-the woodto force it hard against the rotating stonep'The power driving the pressure foot is room:

monly supplied through the piston rod of ,a' fiuid pressure cylinder usually hydraulie' mounted upon the pocket. I

The stage'of grindingomay'be indicated by difl'erent mechanical means'placed on variousstandard grinders, butitis often the case that the pocket: doors must be opened from time, to time'in order that-the stage of the grinding may be determined, and the "need for supplying morewood apprehended. The result is that the operator must be constantly opening the doorsto find out just how matters stand, and if he is lazy and not properlysupervised, or if he has too many machines to care for, itoften .happens that pockets are emptied unknown. to, himand remain empty some. twenty or Application filed August 31, 1920. Serial No; 407,153."

j. i oos-mg Gambian."

Speeificatio'n'of r aei sjrate tj %Pa b nt 1 V; 29,1921;

thirty; minutes, or more. Meanwhile, the. I

grindstone, 'relievedof this pressure, rapidly gains-speed,'esp eciallyif driven by a-water j wheel, and'such sudden gains speed are usually the cause of gr ndstones bursting: Furthermore, when the pocket has at" last emptied, .in order to prepare it for a fresh charge, the operator must reverse. the Valve in orderto retract-the pressure foot, and also open the door; These operations are usually done'by hand- I a It is accordingly. an object of this inven-v tion'todojaway with theseobjections, and this is done by providingineanswhich auto; matically reversethe hydraulic valve, with drawthe pressure foot, andopen the door as soon as the. pocket to: which these things appertain has been emptied. The operatori is thus'immediately apprised of the situa; tion andqean proceedto refill the'pocket without loss of time, This happy result is efi'ected' by causing the movement of the pressure foot itself to operate m'eans'which reverse the valve, andprovidingmeans m0v-. able with the pressure foot for engaging the door and. opening itas the pressure foot isretractedi I In order that the invention may befimore clearly understood reference is had to, the accompanying drawings disclosing one jem bodiment thereoi'and in which; I Figure 1 is'ja side, elevation of a fourpocket grinder, the grindingin eachpocketbeing shown in various'stages; V f

Fig. 2 is a detail view of one of the pockets and its cylinder, showing {thef mechanism whereby hydraulic valve is automatically reversed;

Fig. 3 Y and cylinder shown in Fig. 2, looking toward the left. a r

- Referring now to the drawings, '.1-- reprew is aside elevation of the pocket- .95.

'sentsa "pulp grind'stone ,journal'ed insuit able bearln s 2 and inclosedwith a houslng 'Adj'usta bly mounted upon this housing,"

and radially disposed with reference to the] grindstone, is a series of pockets 4, 5,36and 7.g'Mounted upon; these pockets are cyl-v V cylinder by means of an oscillating valve sure foot is retracted. closes the pocket during grinding. The

invention.

13, this valve being oscillated by means of a lever or arm 1 1 in a manner to be described later. When water is introduced into the upper end of the cylinder the piston forces the pressure foot 15 downwardly and this presses the wood in the pocket against the face i of the grindstone. When the water is introduced into thelower end of the cylinderthis motion is reversed and the pres- A sliding door 28 foregoing arrangement except for the arm 11 is generally old and forms no part of the Attention is now called particularly t Figs. 2 and 3 showing the specific mechanism whereby the hydraulic valve of a cylinder is automatically reversed when its corresponding pocket is emptied, thereby retracting the pressure foot and simultaneously opening the door of the pocket.

Secured to the upper face of the pressure foot is a rod 16 which projects through an opening in the casing which supports the cylinder, as clearly shown-in Figs. 2 and At the upper end of this rod 16 is secured an L-shaped member 17 having a horizontal arm'18 and a vertical arm 19, from which projects a horizontal lug 21. Mounted upon the upper end of the pocket 7 is a slotted casting 20 between the legs ofwhich is journaled an Lshaped latch 22 havinga horizontal arm 23 and a vertical arm 24%. The. upper end of thevertical arm is provided with a hook 25 which is adapted to engage with pin 26 projecting from one end of arm 14.

When the pressure foot is in its uppermost position, the pocket filled with wood, and the valve '13 positioned to allow water to enter the upper end of the cylinder and thus begin the downwardor forward movement of the pressure foot, the parts are ar-. ranged as shown in Figs. 2 and 3. As the pressure foot descends carrying with it rod' 16 and member 17, the valve 13 is held open in the desired forward position by means of arm 14 held in the position shown by means of engagement with latch 22. WVhen the wood has been ground away and the pressure foot lies close to the grindstone, the

horizontal lug 21 on arm 19 of member 17' engages with the horizontal arm 23 of latch 22, thus causing the vertical arm of the latch to swing toward the left and disengage pin.

26. A weight 27 mounted upon the other end of the arm 14; being thus free to fall, operates to reverse valve 13 and causes water to enter the lower end of the cylinder, thus effecting an immediate withdrawal of the pressure foot 15.

The pocket 7 is closed by means of door 28'slidably mounted in guideways 29 and supported, when open, by means of guide rod completion.

30. Thisdoor is automatically opened when the pressure foot is retracted as follows:

'Pivoted upon the vertical arm 19 of the left because of the engagement of a cam.

surface 33 with the pin 32.- As the downward movement continues member 31 rides past the pin 32 and'resumes its normal and vertical position with its hook below the pin;

When the flow of water has been reversed by the tripping of the latch 22, as described above, and the retractive movement of the pressure foot begins, the member 31 engages pin 32 and carries the door upward with it.

The operation of the valves is as follows: Assume that a pocket has been emptied, its pressure foot withdrawn and its door opened. The operator then charges the empty pocket with wood, manually frees pin 32 from hookedmember 31 and lowers the door. He seizesthe handle 34 of arm 14, swings the arm downwardly and secures it in this position by means of latch 22. The valve 13 is thus turned to admit water to the upper end of the cylinder, and pressure is applied to the wood. When the wood has been ground away and the pocket in readiness for recharging, latch 22 is automatically tripped, valve 13 reversed and pressure foot 15 retracted carrying door 28 with it.

The various stages of this operation may be seen in Fig. 1. 'Inthat figure pocket 4 is shown with its door closed and the grinding ust beginning; Pocket 5 is shown with the pressure foot retracted and the pocket being refilled. Pocket 6 is shown as just being emptied, with the valve arm and retaining latch shown in dotted lines in their positions just prior to completion of the grinding, and in solid lines subsequent to The hooked member 31 is below the pin on the door and is in positionto retract the door. The grinding in'pocket 7 is shown as about one-half completed.- The hooked member 31 is shown in the act of riding over the pin on the door.

It will thus be seen that the present invention provides a simple and effective means for automatically, reversing the flow of water, retracting the pressure foot, and opening the door of each pocket the moment that pocket becomes empty and should be recharged. There is thus-no necessity for constant inspection by the operator. Nor is there the danger that the pockets may become empty tion. 7 1

Although one specificflform of apparatus has been shown as particularly well adapted in the absence'of such inspecto accomplish the ends sought, it is to be distinctly understood that the invention in its broader aspects is notto be limited to these details of construction. Neither is it necessarily limited to the grinding of wood,

. as it is clear that it may find application movable with the pressure foot for opening the door as the pressure foot is retracted.

2. In a grinding machine the combinationv of a grinding element, a pocket adjacent the grinding element adapted to receive the material to be ground, a fluid actuated recipro crating pressure foot in the pocket for forcing the material to be ground against the grinding element, a valve controlling the flow of fluid whereby the pressure foot is moved either toward or away from the grinding element, a lever controlling the V terial to be ground against the grinding eleoperation of said valve and normally urged to a position in which the pressure foot is moved away from the grinding element, means for holding said lever in a position in which the valve is opened to move the pressure foot toward the grinding element,

' and means for automatically releasing said holding means and permitting the lever to return to its normal position when the pocket is ready for recharging, and thus retract the pressure foot. 7

3. In a grinding machine the, combination of a grinding element, a pocket adjacent the grinding element adapted to receive the material to be ground, a doo'r on the pocket, a hydraulicallyactuated reciprocating pressure foot in the pocket for forcing the mament, a valve controlling the flow of water whereby the pressure foot is moved either toward or'away from the grinding element,

a weighted lever controlling the operation a i of'said valve, a latch adapted to hold the lever against theaction of its weight in a position such that the valveis turned to force the pressure foot toward the grinding 1 element, and'means movable with the pressure foot for tripping the latch when the pocket is ready for recharging, thus freeing the lever whichv operates the valve to retract the pressure foot, and a member associated 'with'said tripping means for engaging the door and opening it .when the pressure foot is retracted.

'- 4:. A wood-pulp grinder, comprising i combinationiof a grindstone, a pocket adjacent the grindstone adapted to hold the wood to be ground, a door on the pocket,a reciproeating pressure-foot in saidpocket adapted to force the wood against the grindstone, automatic means for retracting the pressure foot when the pocket is ready for recharging and means movable with the pressure foot opening the door as the pressure foot is retracted. I

, 5. A wood-pulp grinder comprising the combination of a grindstone, a pocket adjacent the grindstone adapted to hold the Wood to be ground, a door on the pocket, a hydraulically-actuated reciprocating pressure foot in the pocket adapted to force the wood,

against the grindstone, a hydraulic valve controlhng the directlon of'motion' of sald pressure foot, automatlc means for operate ing the valve to retract the pressure foot vwhen the pocket is ready for recharging and means carried bythe pressure foot for engaging the door and opening it as the presj 7 v6'. Means for opening the door of a Wood- 1 sure foot is retracted.

pulp grinder pocket when the pressure foot is retracted, comprising a rod movable with I the pressure foot, a hooked member pivoted thereto designed to engagea projection on the door when the pressure foot is retracted anda cam'surface on said pivoted hooked member designedto contact with the projection on the door during themovement of the pressure foot toward the grinding element and swing the hooked member so that itinay pass the projection.

In testimony whereof I aflix my si nature.

WILLIAM RITCHIE TIDMA SH. V i 

